Nanoscale Spatial Distribution of Thiolated DNA on Model Nucleic Acid Sensor Surfaces
Nanoscale Spatial Distribution of Thiolated DNA on Model Nucleic Acid Sensor Surfaces
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DOI：
10.1021/nn400659m
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发表时间：
2013-04-01
期刊：
影响因子：
17.1
通讯作者：
Ye, Tao
中科院分区：
文献类型：
--
作者：
Josephs, Eric A.;Ye, Tao
DNA探针分子在传感器表面的纳米级排列对DNA生物传感器和微阵列的分子识别和信号反应具有深远的影响。利用电化学原子力显微镜，我们通过不同的方法直接确定了硫化DNA在纳米尺度上的空间分布。我们发现通过回填法制备的DNA单层的探针密度存在显著的异质性和有限的稳定性，即首先将表面暴露于硫化的DNA中，然后用钝化的烷硫醇“回填”。另一方面，通过将硫代DNA“插入”到预先形成的烷硫醇单分子层中制备的单分子层导致更均匀分布的DNA层。利用表面单个DNA分子的高分辨率图像，我们引入了空间统计来表征DNA探针的纳米级排列。空间分布的随机性得到了表征。通过确定单个分子周围的局部密度，我们观察到探针亚群具有显著不同水平的“探针拥挤”。我们预计，空间统计在DNA单分子层上的新应用可以使一个框架能够理解探针空间分布的异质性，探针间的相互作用，以及最终探针在传感器表面上的活性。
The nanoscale arrangement of the DNA probe molecules on sensor surfaces has a profound impact on molecular recognition and signaling reactions on DNA biosensors and microarrays. Using electrochemical atomic force microscopy, we have directly determined the nanoscale spatial distribution of thiolated DNA that are attached to gold via different methods. We discovered significant heterogeneity in the probe density and limited stability for DNA monolayers prepared by the backfilling method, that is, first exposing the surface to thiolated DNA then "backfilling" with a passivating alkanethiol. On the other hand, the monolayers prepared by "inserting" thiolated DNA into a preformed alkanethiol monolayer lead to a more uniformly distributed layer of DNA. With high-resolution images of single DNA molecules on the surface, we have introduced spatial statistics to characterize the nanoscale arrangement of DNA probes. The randomness of the spatial distribution has been characterized. By determining the local densities surrounding individual molecules, we observed subpopulations of probes with dramatically different levels of "probe crowding". We anticipate that the novel application of spatial statistics to DNA monolayers can enable a framework to understand heterogeneity in probe spatial distributions, interprobe interactions, and ultimately probe activity on sensor surfaces.